Heated frame element for door and window constructions



Nov. 13 1962 ow CONSTRUCTIONS Filed Feb. 19, 1960 /4 OR DOOR AND WINDFIG.

y 5m WI/W United States Patent Ofitice 3,064,110 HEATED FRAME ELEMENTFOR DOOR AND WINDOW CONSTRUCTIONS Jacques Vogler, Downsview, Ontario,Canada, assignor, by mesue assignments, to R.M.P. Industries LimitedFiled Feb. 19, 1960, Ser. No. 9,830 2 Claims. (Cl. 219-19) Thisinvention relates to a heated frame element for door and window framestructure adapted to effect heating of the interior surfaces of a windowor door to obviate moisture condensation and ice formation thereon.

Insulation is ordinarily provided in window glass area by creating adead air space such as by applying a storm window exteriorly or bymounting two panes of glass in predetermined spaced relation sealed attheir edges in fixed relationship. A dead air space between two panesof. glass tends to permit the inner plane to achieve a temperature nearto room temperature thus avoiding condensation of moisture thereon.

Prefabricated window and door frames of recent years, particularly ofthe all metal type such as extruded aluminum box door and window frameconstructions, allow the rapid conduction of heat to the outeratmosphere tending, in the area of the interior metal, to maintain thewindow glass surfaces sufficiently cool in many cases to result in thesubstantial condensation of moisture thereon. This condition may beintensified in modern oflice building construction where glass areas arerequired substantially from ceiling to floor or where the exterior wallis formed entirely of a metal sheeting of high conductivity, as forexample, aluminum.

It is accordingly the main object of this invention to provide a frameelement for window and door frame structures adapted to generate asufficient quantity of added heat to maintain the temperature of theinner surfaces of the window and door at a temperature greater than thecondensation temperature of moisture in the room served thereby.

Other objects of the invention will be appreciated by a study of thefollowing specification taken in conjunction with the accompanyingdrawings.

In the drawings:

FIGURE 1 is a partial perspective elevation of a relatively standardwindow construction embodying the invention; and,

FIGURE 2 is a sectional view on the line 2-2 of FIGURE 1.

Referring to the drawings, window structure is illustrated in place in abuilding wall 11. The window construction itself comprises a box frame12 adapted to be seated within the wall opening 13. The box frame isadapted to carry a sash or window frame 14 supporting one or more panesof glass 15, said window panes being of either single pane or doublepane construction.

According to this invention the box frame or sash frame 12 embodies atleast one frame element such as the frame element 16 carryingtherewithin heating elements of the invention as revealed in more detailin FIGURE 2 and indicated generally therein by the numeral 17.

Heating element 17 is of known metal encased construction having,according to this invention, a predetermined rate of heat generatingcapacity per foot of length. The heat generating rating of such aheating device depends upon the necessary heat energy to replace thatlost from an interior room through a heat loss section one foot wideextending for substantially the height of the room or at least theheight of the window opening having regard to the maximum heat losswhich could occur through the window construction over such area and theminimum outside temperature expected in the locality of 3,064,110Patented Nov. 13, 1962 the installation. It is only necessary, however,to compensate for that heat losswhich would allow the temperature of theinterior surfaces of the window construction. to drop to condensationtemperature of moisture of the interior room having regard to thetemperature of the latter and to humidity conditions. Less than 50 wattsper foot will supply many times the added heat energy normally requiredin cold exterior conditions and severe conditions of heat loss. It hasbeen found that a heater of a rating of the order of about 10 watts perfoot is of highly satisfactory nominal value for a wide range ofcondensation-preventing installations, particularly when same areprovided in two foot length units adapted to be connected inparallel orelectrically in series. A series connection will cut the heat generationto one-half or less depending upon the number of heating units of theinvention so connected, and in this way the installer can control the.heat generation by the electrical connection even after the windowassembly is completed. The installation of two heater units or rods inparallel indicated in FIGURE 2 further facilitates the range of heatgeneration which the installer could accomplish.

The heater units or rods of the invention must have a low surfacetemperature for concealment within the building or window structure. Thesurface area of the heating units therefore must be such as to dissipateheat at a surface temperature less than will be observed that theheating element 18 is supported within a metal body 19 adapted to serveas the glazing stop for the glass pane 20' and having substantialsurface areas, the temperature of which should be approximately roomtemperature and which may be regarded herein as comprising the surfacesof the heating unit itself, the structure being such that the glazingstop forms a part of the heating unit. Thus the invention contemplates aheating element supported within a radiating enclosure such as enclosure19 or the enclosure 20, which latter is adapted to ensure the necessarysafety requirements and which also serves as a frame portion or elementof the window or door frame construction.

The application of the present invention to a door frame constructionembodies the same structural essentials more conveniently applied to adoor sill structure. It will be apparent that a door constructionnormally em bodies a door box frame of which the sill structure formsthe lower member.

If preferred, the frame element 20 may embody a conveniently locatedelectrical switch 21 connected by wire 22 to heating element 17 througha conventional electrical wiring box 23 from which a wire cable 24extends exteriorly of the enclosing frame member 20.

In use, when moisture begins forming on a window pane, the switch 21 maybe switched to the on position to cause heat to be added to the roomexposed surfaces of the window structure. In particular where the windowstructure is of the all-metal glass type covering substantially the fullheight of an exterior wall, the formation of ice will be prevented. Incountries where there is a season of very low temperature it has beenfound that the cost of supplying additional heat to raise thetemperature of inner window Surfaces to above condensation temperatureover a period of some years may be less than the cost of providingsubstantially thermally insulated multiple glass window structures inthe first instance. In any event, the prevention of ice on metal windowstructures extending over large areas in Spite of expensive insulationprecautions is rendered possible by the more simplified and lessexpensive construction afforded by this invention.

It will be apparent from the foregoing that the invention generallyconcerns a frame element for door and window frame structurescomprising: an electric-a1 resist- F. In this respect itance heatingelement of the strip type embodied within a totally enclosing metalcasing, said heating element having a rating of the order of about 10Watts per foot of length; and an enclosure for said heating elementextending thereabout and having a radiating Surface of an area per footof length of said heating element controlling the temperature of saidsurface to less than about 135 F.

It is intended that the present disclosure should not be considered inany limited sense other than that included by the following claimshaving regard to the teachings of the prior art.

What I claim is:

1. An electrically heated frame structure for window constructions orthe like, comprising: a'metallic bottom frame element having ahorizontally disposed top surface, an outer glazing stop fixed to saidsurface and projecting upwardly therefrom, an inverted metal channelmember fixed to said surface inwardly of and parallel to said outerglazing stop and spaced relatively thereto to clamp the lower edge of aglazing unit and glazing strip means between said outer glazing stop andthe outer face of said channel member serving as an inner glazing stop,and a metal-sheathed electric heating unit disposed longitudinallywithin a conduit defined by said inverted channel member and closed bysaid top surface of said bottom frame element.

2. Structure according to claim 1, said metallic bottom frame elementbeing hollow and having an auxiliary metal-sheathed electric heatingunit longitudinally disposed therein.

References Cited in the file of this patent UNITED STATES PATENTS1,633,451 McLaughlin et a1. June 21, 1927 1,665,031 Herman Apr. 3, 19281,822,884 Creighton Sept. 15, 1931 1,848,337 Franzen Mar. 8, 19321,885,127 Milette et a1. Nov. 1, 1932 2,548,363 Gray Apr. 10, 19512,594,465 Lovfald Apr. 29, 1952 2,803,734 Germon Aug. 20, 1957 2,858,408Barroero Oct. 28, 1958 FOREIGN PATENTS 329,513 Switzerland June 14, 1958

